1. Field of the Invention
This invention relates to a loudspeaker coil suspension and dome system that acts to protect the coil from electrical shorting.
2. Related Art
A loudspeaker is a device for converting variations of electric energy into corresponding variations of acoustic energy. To convert the electrical energy into sound, a combination of a diaphragm and a compression driver is coupled to the throat of a horn. The compression driver typically includes a phasing plug made of ferromagnetic material having a plurality of bores between the rear side and the front side of the phasing plug.
Generally, the coil is wrapped around the exterior side of a cylindrically shaped former. The combination of the former and coil are then disposed within an annular magnetic gap enabling free vibration in a direction along the longitudinal axis of the former. The vibration causes a corresponding vibration of the diaphragm generating sound. The suspension needs to flexible in order to accommodate the excursion of the cone or diaphragm. At the same time, the suspension needs to keep the cone or diaphragm from tipping or becoming “de-centered.”
To suspend the diaphragm adjacent to the rear side of the compression driver, the outer perimeter of the diaphragm is coupled to a suspension, which in turn is attached to a mounting plate. With the configurations that have been used in the past, the outer surface of the voice coil is substantially exposed and not insulated.
To generate sound, a static magnetic field, usually produced by a permanent magnet, is applied so that an alternating signal current flowing through the voice coil causes it to vibrate along its cylindrical axis. This in turn causes the diaphragm to vibrate along the axis of the plurality of bores and generate sound waves corresponding to the signal current. The sound waves are directed through the bores toward the front side, which then radiates the sound waves into the air through the horn.
Despite best manufacturing efforts, speakers may fail due to excessive mechanical and thermal stresses. For example, suspensions can fail due to environmental factors such as exposure to heat, UV rays or humidity. Adhesives attaching the suspension to the diaphragm can also fail if applied improperly or if excess mechanical stress is applied to the jointing area. Likewise, adhesives attaching the former to the diaphragm can fail. This happens because applying adhesive between the suspension and the diaphragm, and between the former and the diaphragm, can be a delicate process and possibly misapplied. Another way the loudspeaker might fail is due to over heating of the voice coil. If the voice coil experiences excessive heat expansion, it may come into contact with the sidewalls of the magnetic gap. If this condition occurs and the voice coil is not insulated, the resulting contact between the voice coil and the sidewalls can cause an electrical short circuit and terminal failure will occur.
Another shortcoming of current compression driver devices is that additional acoustic energy may not be provided in high frequency applications. In high frequency applications, additional acoustic energy is desired from the compression driver, but with current designs such additional acoustic energy may not be provided. Therefore, there is a need for a compression driver that can generate additional acoustic energy at high frequency application, a coil and suspension assembly system whose manufacturing process is simplified and a system for protecting the voice coil from experiencing electrical short circuits.